With regard to structures for supporting coils, many different arrangements have been proposed for inductances and for transformers involving the coupling of the magnetic field produced by one coil into another coil. However, in the case of coil structures in which direct coupling of the magnetic fields does not occur to a significant extent, and where very accurate orientation of the magnetic fields is required, little work has been done. Accordingly, a principal object of the invention is to provide an improved coil structure for accurately orienting magnetic fields in at least two mutually orthogonal directions.